Atrial fibrillation (AF) is a major source of cardiovascular disease morbidity and mortality and an important public health problem. It is estimated that the prevalence of AF in the U.S. alone will rise from 2.3 million in 2001 to more than 6 million in 2050. Although our understanding of the prevalence and clinical consequences of AF is sound, important gaps remain. First, clinical guidelines for the management of AF exist, but the extent to which the care of patients with AF in community settings is consistent with these guidelines and is unclear. In addition, how care varies by age, sex, race, geography (e.g., region, urban vs. rural location) and over time is understudied. Second, a number of new technologies have been associated with altered morbidity and mortality in randomized clinical trials, but the extent to which those technologies are used in routine clinical practice is unknown. Finally, we have little empirical evidence about how the resources expended to treat AF translate into improved outcomes. The objective of the proposed project, Patterns of Healthcare Use, Treatment &Outcomes of Atrial Fibrillation: PATH-AF, is to improve our understanding of the aforementioned issues. Our efforts are organized under three Specific Aims: Aim 1 will document the extent to which clinical practice reflects established guidelines and will examine how guidelines-based care and standard care for AF varies by age, sex, race, geography and over time. Aim 2 will analyze the use of emerging technologies to monitor and treat AF patients, including the use of home monitoring devices to measure INR and the use of radiofrequency catheter ablation. Again, in subgroup analyses we will examine differential use by age, sex, race, and geography. Aim 3 will examine the relations between health care use, outcomes and costs in patients with AF. In summary, AF is a major contributor to morbidity and mortality in the population. We bring together a multi- institutional, multidisciplinary team with expertise in AF, health services research, epidemiology, primary care, heart failure, and statistics. We propose to leverage existing cohorts and registries linked with claims to provide a comprehensive picture of healthcare use, treatment, and outcomes of AF in the U.S. The findings will advance our understanding of the treatment of AF in "real-world" settings and build the capacity to use cohort-claims linked data sets to inform current discussions about value in health care. PUBLIC HEALTH RELEVANCE: The proposed research is relevant to the public health in two ways. First, it will provide a comprehensive understanding of the health care of patients with atrial fibrillation in the United States. Second, it will directly answer critical questions of how investments in health care for patients with atrial fibrillation are directly linked to survival and health.